Ionizing electrodes with a dust cleaning mechanism are known and described, for example, in U.S. Pat. Nos. 5,768,087 and 7,969,707, WO 2009/151856 and US 2010/0188793.
In these prior art publications, either centrifugal force is used as an energy source for the cleaning process, or devices are employed that convert linear movement to a rotational movement, or rotational movement to linear movement. The ionizing electrodes are formed as needles or as thin wires.
U.S. Pat. No. 7,408,759 discloses devices for cleaning wire electrodes where the electrode is passed through a bushing. A drawback of this device is the low degree of cleaning, the reason being that because of the need to facilitate the wire sliding inside the bushing during nonlinear back-and-forth motion, the inner diameter of the bushing is made much larger than the wire diameter, and the length of the bushing is many times smaller than the maximum amplitude of back-and-forth motion of the wire. For these reasons only a part of the wire circumference is cleaned.
A common drawback of the all above mentioned devices is their complexity.
SUMMARY OF THE INVENTION
An aim of the present invention is to eliminate the drawbacks of existing devices.
In the proposed invention an ionizing electrode is formed as a thin wire made from a conducting spring material. The electrode is mounted inside a fixed bushing with the ionizing and non-ionizing ends of the electrode protruding from the bushing. During cleaning of the ionizing end from dust the electrode travels inside the bushing owing to the linear back-and-forth movements. The movements are generated by a solenoid which consists of a body made from insulating material, a magnetic conductor and a coil with a core and a return spring located inside it.
Additionally, a high voltage supply terminal is located inside the coil, the return spring being placed between the terminal and one of the core ends, while the non-ionizing end of the electrode protruding from the bushing is fixed at the other end of the core.